Increases in tobacco mechanization over the past four years have been quite dramatic as tobacco farmers, especially in the south and flue-cured regions, have purchased automatic tobacco primers and bulk tobacco barns for use in their tobacco farming operations. Most fully automatic tobacco harvesters presently in use are of the high clearance self-propelled type such as shown in U.S. Pat. No. 3,841,071, and such as the high clearance self-propelled "Roanoke" tobacco harvester manufactured by Harrington Manufacturing Company of Lewiston, North Carolina. These self-propelled automatic tobacco harvesters are available in both one and two-row models. Certainly the "Roanoke" self-propelled harvester has met with great commercial success and acceptance by tobacco farmers. However, some farmers with small and moderate tobacco acreages, such as a farmer with 10 to 20 acres, have found it difficult to justify the investment required for a high clearance self-propelled tobacco harvester in terms of the expected return and profit from such small tobacco acreages. Still the small tobacco farmer faces the same labor scarcity as large tobacco farmers, and these small tobacco farmers desire to continue a tobacco farming operation. Thus, the need still exists for the small tobacco farmer to mechanize, but at a reasonable investment in terms of crop size and expected returns from their tobacco crop.
There has been some attempt to provide the smaller tobacco farmers with an automatic tobacco harvester at a price significantly below the cost of a conventional high clearance self-propelled automatic tobacco harvester. Because almost all tobacco farmers have at least one conventional farm tractor for other farm use, it has been attractive to explore the possibility of a tractor mounted harvester or a pull type harvester, in either case the power being provided by the conventional farm tractor to move the harvester through the field and to drive the various working components thereof such as defoliators and conveyors forming a part of the harvester.
Tractor mounted harvesters have just recently been introduced to tobacco farmers, these tobacco harvesters being of the general type manufactured by Lebro Manufacturing, Inc., Waycross, Georgia, and referred to as the G S & H Tractor Mounted Harvester. Generally, tractor mounted tobacco harvesters involved heavy and cumbersome frame work that requires substantial time and effort to mount and dismount the same about the tractor. In addition, such harvesters normally are provided with a rear cross conveyor for conveying the defoliated leaves from the harvester into a trailer being pulled by the same tractor in which the harvester is mounted. Often it becomes difficult to turn and maneuver both the tractor and trailing trailer with the harvester mounted on the tractor. But perhaps the most significant problem faced by the tractor mounted harvester is in being able to harvest at least two rows on one side of the tractor middle or skip row provided in the tobacco field for the tractor to pass. This is because many tobacco farmers find it desirable and advantageous to skip every fifth row in a tobacco field during the planting operation, so as to leave the fifth row open for the tractor to pass therethrough during particular harvesting operations. This has become an almost universally accepted cultural practice where a farm tractor is used in harvesting. In multi-pass harvesting where it is required that the harvester pass along each row several times during the tobacco harvesting season, it becomes important for the tractor mounted harvester to have the capability to reach an inside row or the row outwardly of the outside row that runs adjacent the fifth row or tractor path. This is being done by providing a transverse frame as a part of the tobacco harvester wherein the entire defoliator assembly and associated conveyors are moved laterally back and forth from a first position where the defoliator assembly aligns with the outside row to an extended position where the same defoliator assembly aligns with the inside row. It is very difficult to shift the defoliator assembly back and forth with respect to the tractor in order to accommodate both outside and inside rows. In addition, when the defoliator assembly is extended to a position for harvesting the inside row, often the weight of the defoliator assembly in this extended position disturbs the balance of the tractor and the harvester mounted thereon. To compensate for this some means for counter balancing the entire tractor and harvester structure is provided for, although rarely is such counter balancing completely effective.
It should be pointed out that one alternative to the problem discussed above with respect to requiring the defoliator assembly itself to be shifted relative to the harvester's main frame to accommodate outside and inside rows, is that the farmer could skip every third row in the tobacco field and consequently there would be only one row on each side of the skip row to be harvested, and this would not require shifting the defoliator assembly as the two outside rows could be harvested by passing the tractor through the skip row twice, once in each direction. But this is not an attractive alternative, because greater land area is required for a given quantity of tobacco, and many farmers today do not have the necessary suitable land for this type of planting. In addition, in either case with the tractor mounted tobacco harvester, the transverse width of the tractor and harvester as combined is substantially greater than the width of the tractor and generally a wider skip row is required for the tractor mounted harvester to pass. This creates inconvenience in planting and cultivating the tobacco crop, and often a non-standard row spacing is required.
Finally reference is made to U.S. Pat. No. 3,962,850 which generally discloses a trail type tobacco harvester adapted to be connected to and pulled through the field by a tractor. Again many of the problems associated with the conventional tractor mounted tobacco harvester is present here. Principally, this type of trail harvester is again provided with a defoliator assembly that requires lateral shifting independently of the harvester's main frame to accommodate either of two rows disposed on one side of the skip row or tractor passing middle formed within the field. Also, where the pull type harvester is provided with a cross conveyor, and a trailer pulled by the tractor receives tobacco from the cross conveyor, the combined harvester and trailer structural network connected to the tractor makes the entire network, i.e., tractor, harvester, and trailer, very difficult to turn, handle, and maneuvers, especially at the ends of the rows where the tractor, harvester, and trailer must be turned in order to enter the field for harvesting another row.